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United States Patent |
5,697,247
|
Zehr
|
December 16, 1997
|
Apparatus for measuring the thickness and/or irregularity of slivers
Abstract
The invention relates to a device for measuring the thickness and/or
irregularity of slivers, with a compacting part (2) compacting the sliver
and with a measuring part which has a gutter-like guide conduit (8) for
the compacted sliver and a sensing member (10) which senses the sliver
mechanically and which is adjustable relative to the guide conduit. In
order to allow more accurate measurement, the sensing member is likewise
of gutter-like design in a region in contact with the sliver and forms a
kind of guide conduit (15), so that, in the measuring part, the sliver
runs through a guide conduit consisting of a fixed part (13) and of a part
(14) adjustable relative to the fixed part (13). The adjustable part is
fastened to deflectable carriers (11, 12), and the measurement of the
thickness and/or irregularity of the sliver is carried out by measuring
the adjustment of at least one of the said carriers.
Inventors:
|
Zehr; Jurg (Uster, CH)
|
Assignee:
|
Zellweger Luwa AG (Uster, CH)
|
Appl. No.:
|
673503 |
Filed:
|
July 1, 1996 |
Foreign Application Priority Data
| Jun 29, 1995[CH] | 01 908/95 |
Current U.S. Class: |
73/160; 73/37.7 |
Intern'l Class: |
D01H 005/00 |
Field of Search: |
73/37.5,37.7,159,160
19/239,240
|
References Cited
U.S. Patent Documents
3593566 | Jul., 1971 | Loopuyt | 73/37.
|
3822590 | Jul., 1974 | Tharpe et al. | 73/160.
|
3854330 | Dec., 1974 | Wildbolz | 73/160.
|
3925850 | Dec., 1975 | Lytton | 73/160.
|
3990292 | Nov., 1976 | Stern | 73/37.
|
4122703 | Oct., 1978 | Davis | 73/37.
|
4184361 | Jan., 1980 | Erben | 73/37.
|
4318299 | Mar., 1982 | Morf | 73/160.
|
4481820 | Nov., 1984 | Thomann | 73/160.
|
4706014 | Nov., 1987 | Fabbri | 73/160.
|
4766647 | Aug., 1988 | Ackermann, Jr. | 73/160.
|
4864853 | Sep., 1989 | Grunder et al.
| |
5461757 | Oct., 1995 | Leifeld | 19/239.
|
Foreign Patent Documents |
0 069 833 | Jan., 1983 | EP.
| |
1 50 487 | May., 1971 | DE.
| |
Primary Examiner: Biegel; Ronald L.
Attorney, Agent or Firm: Burns, Doane, Swecker & Mathis, LLP
Claims
What is claimed is:
1. Apparatus for measuring the thickness and/or irregularity of slivers
comprising means providing a gutter-like guide conduit for the sliver; a
sensing unit of gutter-like design for sensing the sliver mechanically,
said sensing unit including a fixed first part and a second adjustable
part fastened to at least one deflectable carrier and being moveable by
the sliver relative to said first part to sense the thickness of the
sliver; and a distance-measuring system isolated mechanically from the
carrier for measuring movement of said adjustable part of said sensing
unit.
Description
FIELD OF THE INVENTION
This invention relates to apparatus for measuring the thickness and/or
irregularity of textile slivers. It is concerned particularly with sliver
measurement apparatus having a measuring part provided with a gutter-like
guide conduit for the sliver and a sensing member which senses the sliver
mechanically and which is adjustable or deflectable relative to the guide
conduit.
BACKGROUND OF THE INVENTION
Measuring apparatus of this general type is known, for example, from U.S.
Pat. No. 4,864,853. This device contains a funnelshaped compacting member
and a measuring member on the latter for measuring the thickness of a
sliver running through a measuring conduit. In this case, the sliver is
sensed by a leaf spring provided with strain gauges and which forms a
sensing and measuring member. In the region of the leaf spring, the
measuring conduit has a gutter-shaped design with a semicircular
cross-section.
In this known device, there is the possibility that the leaf spring will
heat up as a result of friction with the sliver. However, the strain
gauges are highly sensitive to temperature. This means that they may
supply different measured values depending on the temperature, and
additional measures for compensating these influences have to be provided.
A further disadvantage arises because the measuring conduit is closed off
on one side by the leaf spring and in this region has corners which are
usually not filled by the sliver. This results in a non-uniform filling of
the measuring conduit by the sliver, which impairs the measuring accuracy.
Since the leaf spring is connected to a measuring system so as to be
releasable only with difficulty, adaptation to different measuring ranges,
for example by exchanging the leaf spring or the measuring system, is
somewhat complicated.
SUMMARY OF THE INVENTION
A feature of the present invention is that it provides a device which
avoids the disadvantages mentioned and which allows more accurate
measurement of the thickness and/or irregularity of a sliver.
This is achieved in that the measuring conduit has a deflectable or
adjustable part which is in contact with the sliver so that it may move
slightly relative to the sliver axis. The moveable part has a gutter-like
design including a curved surface which together with a corresponding
surface of an adjacent fixed part provides a passage of substantially
closed cross section for the sliver. This moveable part is mounted on
resilient carriers. At the same time, the deflection of the adjustable
part caused by the sliver is recorded, preferably contactlessly. The
measuring means is therefore separated from the part which is moved by the
sliver. This can also be guaranteed by recording the deflection not on the
adjustable part itself, but on the resilient carriers.
The advantages afforded by the device according to the invention are to be
seen, in particular, in that, on the one hand, the actual measuring
element can be separated thermally and mechanically from those elements
which are in contact with the sliver. Moreover, the construction provides
a sliver measuring conduit which preferably has a circular or oval
cross-section, and in any case forms a limiting face which runs
continuously, that is to say has no sharply changing radii or corners.
This cross-section can be filled completely by the sliver without
difficulty. Because the measuring element and that element which is in
contact with the sliver are not coupled, they are both also easily
exchangeable and the entire device can consequently easily be adapted to
the properties of the sliver. Furthermore, measuring elements having a
wider measuring range can be used.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in more detail below by means of an example and
with reference to the accompanying figures, of which
FIG. 1 shows a section through a perspective representation of an
embodiment according to the invention,
FIG. 2 shows a section through part of the device,
FIG. 3 shows a cross-section through the part of the device according to
FIG. 2,
FIG. 4 shows a longitudinal section through the part of the device
according to FIG. 2, and
FIG. 5 shows a perspective view of the part according to FIG. 2, and
FIG. 6 is a view similar to FIG. 5, but showing a modified construction.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows a device 1 according to the invention in its environment. It
includes a so-called entry funnel 2 on one side of the device 1 and driven
draw-off rollers 3, 4 for the sliver on the other side. The device 1 is
arranged in a housing 5, in which a measuring part 6 and a measuring
member 7 are mounted. The measuring member 7 is part of a non-contacting
displacement measuring system which can measure a distance contactlessly.
Such equipment can be purchased from MICRO-EPSILON MESSTECHNIK GmbH & Co.
KG, Konigbacherstrasse 15, D-8359 Ortenburg-Dorfbach, Germany. In such
systems, a coil potted in a housing is energized by a high frequency
current to produce a magnetic field. Such field would extend to a
conductive portion of the part 6 to induce eddy currents there which, in
turn, would cause impedance variations in the coil proportional to
displacements of the target portion of the part 6. The impedance
variations are used to generate voltage variations directly proportional
to the distance.
Alternatively, the measuring member 7 can also be designed as a pressure
gauge or dynamometer which touches the measuring part 6, for the measuring
principle used in this case is not always critical, as long as it allows
the desired measuring accuracy. It is therefore also possible to have
mechanical distance meters, in which there is a preferably releasable
mechanical connection between the measuring part 6 and the measuring
member 7.
FIG. 2 shows in particular the measuring part 6, which has a compacting
part 8, a guide conduit 9, a sensing member 10 and deflectable carriers 11
and 12. The sensing member 10 is that part of the measuring part 6 which
is in contact with the sliver, not shown here, for measurement, and it
consists of a fixed part 13 and of a movable or adjustable part 14. The
sensing member 10 is likewise of gutter-like design in a region in contact
with the sliver and forms a kind of guide conduit 15. This is defined
relative to the sliver by the fixed part 13 on the one hand, and by the
adjustable part 14, on the other hand. As seen in the direction of
movement of the sliver, the guide conduit 15 or the adjustable part 14 is
preceded by a closed approach conduit 16, the cross-sectional area of
which is larger than the cross-sectional area of the guide conduit 15,
this being indicated here by a corresponding choice of diameters. This
applies even when the adjustable part 14 is in a position of maximum
deflection with respect to the fixed part 13. The guide conduit 15 is
preferably formed by two half-shells, each of semicircular cross-section,
one half-shell belonging to the fixed part 13 and one halfshell to the
movable part 14. An exit conduit 17 follows the guide conduit 15 and, like
the approach conduit 16, has a larger cross-section than the guide conduit
15. The fixed and adjustable parts 13, 14 of the measuring member 10 are
separated from one another by a separating slit 18 which, in the region of
the fixed and of the adjustable parts, has a portion 19, in which it runs
parallel to an axis 20 of the measuring part. The separating slit 18 has
portions 21 and 22 running radially in the region of the ends of the
adjustable part.
FIG. 3 shows a section through the measuring part 6 in the region of the
guide conduit 15. In this can be seen the already above mentioned
half-shells 23 and 24 as well as parts 25 and 26 of the separating slit
18. A thin cover 28 can optionally be fastened to one of the half-shells
23 or 24, covering the separating slit 18 and preventing the sliver from
being jammed in it. Nevertheless, other solutions for preventing this
problem are also known.
The approach conduit 16, the guide conduit 15 or the sensing member 10 and
the exit conduit 17 can be seen once again in FIG. 4, specifically from an
angle of view rotated through 90.degree. relative to FIG. 2.
FIG. 5 shows once more, in a view from outside, the fixed part 13 and the
movable part 14 as well as the carriers 11 and 12 which are designed
resiliently in the manner of a leaf spring.
FIG. 6 shows, in a further version, the fixed part 13 and the movable part
14' which, here, is fastened only to a single carrier 12. The movable part
14' can thereby be tilted away even more easily relative to the fixed part
13. This additional movement can be recorded by a further measuring system
29 in addition to the measuring system 7 referred to in connection with
FIG. 1 or can be prevented by a guide acting in a region 30. Instead of
the measuring systems 7 and 29, known strain gauges 33 can also be
attached directly to the carrier 12. These are preferably connected to
releasable connections in the entry funnel 2, so that the measuring part
shown is exchangeable in this case too.
The mode of operation of the device according to the invention will now be
described. The sliver enters via the entry funnel 2 and, drawn by the
draw-off rollers 3 and 4 in a way known per se, runs through the measuring
part 6. At the same time, it is compacted in the entry funnel 2 and in the
compacting part 8 and passes thus into the approach conduit 16. Depending
on the density of the sliver, the two halfshells 23, 24 or parts 13, 14
are urged more or less apart from one another in the sensing member 10
counter to the force of the resilient carrier or carriers 11, 12. The
sliver subsequently runs through the exit part 17. As a result of the
urging of the parts 13 and 14 apart from one another, the movable part 14
is newly positioned at least temporarily for the duration or length of a
thick or thin place in the sliver, this being recorded by the measuring
member 7. The latter continuously emits signals which correspond to the
current position of the movable part 14. At the same time, as shown in
Figure 1, the position of the part 14 can also be recorded via a portion
27 of a carrier. In order to improve measuring accuracy, the position of
the adjustable part 14 can also be recorded at other or a plurality of
points by a plurality of measuring members 7, 29. This is, for example, in
order to monitor the parallelism of the two half-shells 23, 24 and
increase measuring accuracy.
As is evident from FIG. 1, the movable part can also have a stop 31 which
limits the movement of the movable part relative to the housing 5 and
which thus prevents the carriers or measuring elements connected to them
from being overstretched. Since the slivers to be measured may also cause
a large amount of dust, it is possible to blow air into the housing 5 via
an orifice 32 and thus build up excess pressure which keeps away the dust
which could infiltrate from below.
The measuring part 6 can be exchanged easily in order to adapt the device
to slivers having another density, other material or another speed. For
this purpose, the measuring parts 6 can differ from one another in the
shape of the half-shells 23, 24, the return force of the carriers 11, 12
or the mass of the adjustable part 14. In general, however, this measuring
part 6 has a low mass and therefore a high natural resonant frequency.
Shorter defects in the sliver can thus also be recorded.
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